Using Protobuf in Golang

This is a creation in Article, where the information may have evolved or changed.

Installing GOPROTOBUF

1. get protobuf compiler Protoc from https://github.com/google/protobuf/releases( binary version available for download to Windows

wget Https://github.com/google/protobuf/releases/download/v2.6.1/protobuf-2.6.1.tar.gztar ZXVF PROTOBUF-2.6.1.TAR.GZCD Protobuf-2.6.1./configuremakemake installprotoc-h

2. get Goprotobuf  Protobuf provided   compiler plug-in Protoc-gen-go should be added path  environment variable so that Protoc  can find Protoc-gen-go

This plugin is Protoc used to compile a . proto file is a Golang source file that can be used by this source file to define the messages in the . Proto file.

Go get github.com/golang/protobuf/protoc-gen-gocd Github.com/golang/protobuf/protoc-gen-gogo buildgo installvi/etc/ Profile add $gopath/bin to the environment variable source profile

3. get The support library provided by GOPROTOBUF, including functions such as encoding (marshaling), decoding (unmarshaling), etc.

Go get github.com/golang/protobuf/protocd github.com/golang/protobuf/protogo buildgo Install

Using Goprotobuf
Here is an example to illustrate usage. First create a. proto file Test.proto:

Package Example;enum FOO {X = 17;}; Message Test {Required String label = 1;optional Int32 type = 2 [default=77];repeated Int64 reps = 3;optional Group Option Algroup = 4 {Required String requiredfield = 5;}}

Compile this. proto file:

Protoc--go_out=. *.proto

The protobuf compiler plugin protoc-gen-go provided by GOPROTOBUF is used here through –go_out. At this point we will generate a source file named Test.pb.go.

Before using it, let's look at some of the available interfaces for each PROTOBUF message in Golang:

1. Each PROTOBUF message corresponds to a golang struct

2. Message that the domain name Word is camel_case in the corresponding Golang structure for CamelCase

The setter method does not exist in the Golang struct that corresponds to the li>

message, only the struct can be assigned directly, and some auxiliary functions may be used when assigning values, for example:

msg. Foo = proto. A getter method exists in the Golang struct body of the String ("Hello") 

3. Message that returns the value of the field and returns a default value if the field is not set to a value

4. Message non-repeate The field of D is implemented as a pointer to nil when the field is not set in the

5. Message repeated field is implemented as slice

6. When accessing enumeration values, use the Format enumeration type name _ Enum name (more content can Read the generated source directly)

7. uses Proto. Marshal  is encoded using Proto. The Unmarshal function decodes the

Now we're writing a small program:

package mainimport  (     "Log"     //  Auxiliary library       "Github.com/golang/protobuf/proto"     // test.pb.go  path       "Example") Func main ()  {    //  Create a message  Test     test := &example. test{        //  setting the value of a field using an auxiliary function          label: proto. String ("Hello"),         type:  proto. Int32 (+),         optionalgroup: &example. Test_optionalgroup{            requiredfield:  proto. String ("Good bye"),        },    }     //  encode the     data, err := proto. Marshal (tesT)     if err != nil {         Log. Fatal ("marshaling error: ",  err)     }    //  decode     newtest := &example. Test{}    err = proto. Unmarshal (data, newtest)     if err != nil {         log. Fatal ("unmarshaling error: ",  err)     }    //  test results     if test. Getlabel ()  != newtest.getlabel ()  {        log. Fatalf ("Data mismatch %q != %q",  test. Getlabel (),  newtest.getlabel ())     }}